Crosscutting assembly embodying rotary knife means

ABSTRACT

A rotary crosscutting assembly for cooperation with a counter knife in cutting a moving web of paper, cardboard or like material comprising rotary head means, at least two knife means carried by and extending longitudinally of said head means, means mounting one of said knife means for displacement in a tangential direction relative to the axis of rotation of said head means to impart compound movement to said one knife means relative to the axis of said head means between an operative cutting position at a particular radial distance from said axis to an inoperative position at a lesser distance from said axis and means for releaseably holding said one knife means at said positions.

United States Patent CROSSCUTIING ASSEMBLY EMBODYING ROTARY KNIFE MEANS 6 Claims, 5 Drawing Figs.

US. Cl 83/563, 83/677 Int. Cl B26d 1/12 Field of Search 83/563, 676, 677

[56] References Cited UNITED STATES PATENTS 759,071 5/l904 Brooks 83/677 3,370,628 2/1968 Waldrop 83/677 X Primary Examiner-William S. Lawson; Attorney-Burgess, Dinklage and Sprung ABSTRACT: A rotary crosscutting assembly for cooperation with a counter knife in cutting a moving web of paper, cardboard or like material comprising rotary head means, at least two knife means carried by and extending longitudinally of said head means, means mounting one of said knife means for displacement in a tangential direction relative to the axis of rotation of said head means to impart compound movement to said one knife means relative to the axis of said head means between an operative cutting position at a particular radial distance from said axis to an inoperative position at a lesser distance from said axis and means for releaseably holding said one knife means at said positions.

CROSSCUTTING ASSEMBLY EMBODYING ROTARY KNIFE MEANS The present invention relates to a crosscutting assembly for cutting moving webs of paper, cardboard and similar material, and more particularly to a crosscutter assembly embodying a rotary knife carrying drum or head provided with two or more knives.

Crosscutting arrangements including a rotary drum or knife carrier equipped with, for example, two knives are known to possess the advantage of being able to operate within a range of enlarged sizes, that is they can cut sheets whose lengthmeasurements vary substantially with respect to each other.

However, a necessary prerequisite for obtaining such an enlarged range of sizes when utilizing rotary knife carrying drums is the feasibility of allowing one knife to be moved out of its operative position. In order to accomplish this objective, the state of the art knows of knife carrying drums in which the movable knife can be moved out of or into its operative position, respectively, by a radial displacement. With such an arrangement in addition to suitable guide and support means for the knife to be displaced, there is requireddisplacement control means, such as levers, bellcranks, crankshafts, toothed racks or the like which control means represent not only a relatively high cost factor but due to complicated constructional aspects, also cause inevitable or unavoidable play of movement as a result of such a multiplicity of members and parts. This play of movement does not assure accurate and exact parallel shifting or displacement of the movable knife nor does it assure a precise terminal or end position which is of great importance in providing undisturbed cooperation with the stationary counter knife for obtaining clean cuts.

Furthermore, in installations or assemblies where the movable knife is capable of only radial movement in a slot or a guide, it is necessary to loosen the clampingor shimming arrangement that locks the knife in position before the knife can move radially. Such repeated loosening and tightening of the knife clamping means enhances the possibilities of having play arise between the parts and of having the cutting edge of the knife assume an inaccurate position.

Accordingly, this invention has for an object to provide a rotary crosscutting assembly having at least two knives at least one of which is retractable or displaceable from a cutting position at a particular radial distance from the axis of rotation to an inoperative position inwards of said radial distance or closer to the said axis in which simple and economical structural means are included for effecting such retraction or displacement in such a manner as to preserve the precise positioning and adjustment of the knife.

Consistent with the foregoing object, it is another object of this invention to provide a rotary drum-type crosscutting assembly in which one or more knives or their associated knife mounting means or supports which are mounted adjacent the circumference of the knife carrying drum or cylinder are so constructed that by imparting a so-called tangential displacement thereto along a surface area that lies parallel to the axis of rotation of the drum, the knife or knives can move into or out of the cutting position. In effecting this displacement, the knife performs a compound movement that includes a component inwards of the circumference of the circle or cylinder described by the knife in operative cutting position and a component that is transverse of the axis of rotation of the drum.

A further object of this invention is to provide a crosscutting assembly in which the surface area which lies parallel to the axis of rotation and the plane determined by the cutting edge of the knife and the centerline or axis of the rotary drum intersect each other at an obtuse angle.

Consistent with the immediately aforegoing object, it is an additional object to provide a rotary crosscutting assembly in which the surface area that is disposed parallel to the axis of rotation of the drum is the joint or separating face of a knife mounting means or support which constitutes a section or segment ofthe rotary drum or cylinder.

A further object of the invention is to provide a rotary crosscutting assembly in which simple and economical constructional components are provided to effect necessary bodily displacement of one knife means out of effective cutting position by only a limited amount of displacement in a tangential direction.

It is a still further object of this invention to provide a rotary crosscutting assembly for cooperation with a stationary knife means for cutting moving webs of paper, cardboard or the like materials which includes rotary cutting means including at least two parts, a knife means carried by, fixed to and extending longitudinally of one of said parts, said parts including cooperating guide surfaces extending transversely of and parallel to the rotary axis of said cutting means such that in any plane taken perpendicular to such axis the line of said surfaces in such plane extends on a chord of the circle described by the knife so that displacement of one part relative to the other along said surfaces imparts a compound movement to said knife means between an operative position at a particular radial distance from said axis and an inoperative position inwardly of said particular radial distance with such compound movement including a component of movement transversely of such axis and a component of movement inwards of particular radial distance, means operably related between said parts for imparting such relative displacement and means for releaseably clamping said parts together to hold said knife means at said positions.

Further and more specific objects and advantages will be apparent from the following description when taken in connection with the accompanying drawings a preferred preferred embodiment of the invention in which:

FIG. 1 is a fragmentary diagrammatic view partly in vertical cross section and partly in elevation, illustrating a rotary cross cutting assembly according to the present invention in which the knife carrying drum, head or cylinder is equipped with two knife means;

FIG. 2 is a fragmentary front elevational view of the knife carrying drum;

FIG. 3 is an end view of the knife carrying drum or head illustrating one knife drum displaced out of operative cutting position;

FIG. 4 is a vertical cross-sectional view through the knife carrying drum and taken along line 4-4 of FIG. 2; and

FIG. Sis a similar view taken along line 5-S of FIG. 2.

As illustrated in FIG. 1, the crosscutting assembly or installation includes a continuously rotating knife carrying drum or head means 1, which in this embodiment carries two diametrically opposed knives 2 and 3 on its circumferential area. The knives 2 and 3 are secured or fixed in a known manner to knife mounting means or holders by shims and clamping screws. These knives revolving with the drum or head in the direction of arrow A cooperate with a stationary counter knife 4. The paper or like web 5 to be cut into separate sheets is fed to the cutting position from a supply roll, not shown, severed into sheets 5 at the cutting position, taken along by conveyor belt means 6, 7 and fed to a stack or other processing location, not shown.

The cross-sectional views of FIGS. 4 and 5 illustrate the essential constructional characteristics of the rotary crosscutting installation in which knife means 2 is stationary or fixed with respect to drum or head means I and knife means 3 is movable or displaceable with respect to the head means. The basic shape of drum or head 1 is constituted by an essentially cylindrical hollow body provided with two flattened surface areas 8 and 9 lying chordwise of the body. Trunnion or axle means such as 1' support the body for rotation about the axis of such trunnion means. The stationary knife 2 is secured to a strip 10 constituting a knife holder. This strip I l) is mounted in fixed relation on the smaller flattened surface area 8 by means not shown, so that the cutting edge of knife 2 describes the effective cutting circle 13 during a cutting operation. The knife means 3 is mounted and secured in a knife holder or support strip 12 secured to a strip or segment I1 having a flat undersurface which cooperates with surface area 9 so that the support strip 11 and knife 3 are in effect tangentially displaceably along area 9. a

ln FIGS. 1, 4 and 5 the displaceable knife 3 is shown in its cutting position, i.e. in the position in which the cutting edge of knife 3 revolves on the effective knife circle 13, cooperab ing, as does knife 2, with counter or stationary knife 4. Now, in order to enable substantial enlargement of the range of sizes within which the transverse cutting installation can operate,

the knife 3, as shown in FIG. 3, is brought into a nonoperative resting position by tangentially displacing knife support 11. As a result of the special disposition of surface area 9 which is such that said surface area 9 and the plane 14 determined by the edge of knife 3 and the centerline or axis knife drum or head I enclose an obtuse angle a, knife 3 is allowed farreaching outward movement from its operative position with only a very short tangential displacement of knife support 1 1.

To provide for and impart the displacement to knife 3, the arrangement includes a stationary stop strip or abutment 15 secured by bolt means 15' to one end of surface area 9. The undersurface of block or strip 11 is provided with at least one rib 18 engageable in a groove 19 that constrains block 11 to so move that knife 3 remains parallel to the axis of the cutter drum. At suitable intervals along the length of strip 11 recesses 20 and 21 are provided. The recesses 20 do not extend down to the surface area 9 of drum 1 but terminate above such surface to leave webs 22 which are provided with slots 23 through which pass headed clamping bolts 16 that engage in threaded holes in the web of hollow body 1 that defines flat surface area 9. Within recesses 21 are blocks 24, only one of which is illustrated, that are bolted or otherwise fastened to drum 1. The blocks are provided with a threaded bore within which is engaged an externally threaded spindle 17. The end of such spindle is provided with a head 25 that is disposed in a recess in the strip 11. The head can turn on this recess but is restrained-against axially movement out of the recess.

To effect displacement of the knife 3 from operative position wherein the front of strip 11 abuts stop 15, FIGS. 4 and 5, the clamping bolts 16 are loosened, the spindle 17 is turned and strip 11 moves along surface 9 in a tangential direction to impart a compound movement to knife 3 that disposes the cutting edge thereof inwardly of the effective cutting circle 13. After the strip 11 reaches the position shown in FIG. 3 where the arcuate periphery of strip 11 coincides with that of head 1, the clamping bolts 16 are retightened and cutting continued with only knife 2 effecting a cut so that the severed sheets are longer than when both knives are cutting.

it is therefore clear that only a short displacement of knife 3 in a direction parallel to surface area 9 moves the knife edge inwardly of the effective cutting circle 13.

The invention is not to be limited to a hollow drum construction nor to one in which the stationary knife 2 is mounted in a strip that is secured to a flattened area such as at 8.

The important concept of this invention comprises a rotary cutter assembly consisting of at least two parts, a knife means carried by and secured to one of such parts, cooperating guide surfaces on the parts extending transverse of the axis of rotation, means for displacing the knife carrying part relative to the other part in the plane of such surfaces and means for releasably clamping the parts together in one position in which the knife means is located at such a particular radial distance from the axis of rotation as to describe an effective cutting position and another and inoperative position inwardly of such distance.

What I claim is:

l, A rotary crosscutting assembly for cutting moving webs of paper, cardboard or like material comprising a head means, knife means carried by said head means and extending longitudinally thereof, said head means having a surface area lying in a'plane parallel to the axis of rotation of said head means, said knife means including at least one displaceable knife means, means for moving said displaceable knife means between a cutting position at a particular radial distance from said axis to an inoperative position at a lesser radial distance from said axis, said last-mentioned means imparting a displacement in a tangential direction to said displaceable knife on said surface area, said head means including at least two parts, said one displaceable knife means being carried by one of said parts, cooperating guide surfaces on said parts, one of said guide surfaces constituting said surface area, and the means for moving said one displaceable knife means being operably related between said parts.

2. A rotary crosscutting assembly for cutting moving webs of paper, cardboard or like material comprising a fixed knife means and for cooperation therewith a rotary head means, knife means carried by said head means and extending longitudinally thereof, said head means having a surface area lying in a plane parallel to the axis of rotation of said head means, said knife means including at least one displaceable knife means, means for moving said displaceable knife means between a cutting position cooperating with said fixed knife means at a particular radial distance from said axis to an inoperative position at a lesser radial distance from said axis and said last-mentioned means imparting a displacement in a tangential direction to said displaceable knife on said surface area.

3. A rotary crosscutting assembly as claimed in claim 1 in which the plane of said surface area and the plane passing through the cutting edge of said displaceable knife means and the axis of rotation of said head intersect one another at an obtuse angle.

4. A rotary crosscutting assembly as claimed in claim 3 in which said head is substantially cylindrical in cross section, a mounting means for said displaceable knife means, said mounting means having a guide surface cooperating with and parallel to said surface area and said mounting means being shaped substantially as a segment of such head.

5. A rotary crosscutting cutting assembly as claimed in claim 1 in which said one part has slots therethrough, said other part having threaded bores therein underlying said slots and headed bolt means disposed through said slots and threadedly engaged in said bores for releasably clamping said parts at said positions.

6. A rotary crosscutting assembly as claimed in claim 5 in which said one part has at least one recess therein interrupting the associated guide surface, and the means operably related between the parts being disposed in said recess. 

1. A rotary crosscutting assembly for cutting moving webs of paper, cardboard or like material comprising a head means, knife means carried by said head means and extending longitudinally thereof, said head means having a surface area lying in a plane parallel to the axis of rotation of said head means, said knife means including at least one displaceable knife means, means for moving said displaceable knife means between a cutting position at a particular radial distance from said axis to an inoperative position at a lesser radial distance from said axis, said lastmentioned means imparting a displacement in a tangential direction to said displaceable knife on said surface area, said head means including at least two parts, said one displaceable knife means being carried by one of said parts, cooperating guide surfaces on said parts, one of said guide surfaces constituting said surface area, and the means for moving said one displaceable knife means being operably related between said parts.
 2. A rotary crosscutting assembly for cutting moving webs of paper, cardboard or like material comprising a fixed knife means and for cooperation therewith a rotary head means, knife means carried by said head means and extending longitudinally thereof, said head means having a surface area lying in a plane parallel to the axis of rotation of said head means, said knife means including at least one displaceable knife means, means for moving said displaceable knife means between a cutting position cooperating with said fixed knife means at a particular radial distance from said axis to an inoperative position at a lesser radial distance from said axis and said last-mentioned means imparting a displacement in a tangential direction to said displaceable knife on said surface area.
 3. A rotary crosscutting assembly as claimed in claim 1 in which the plane of said surface area and the plane passing through the cutting edge of said displaceable knife means and the axis of rotation of said head intersect one another at an obtuse angle.
 4. A rotary crosscutting assembly as claimed in claim 3 in which said head is substantially cylindrical in cross section, a mounting means for said displaceable knife means, said mounting means having a guide surface cooperating with and parallel to said surface area and said mounting means being shaped substantially as a segment of such head.
 5. A rotary crosscutting cutting assembly as claimed in claim 1 in which said one part has slots therethrough, said other part having threaded bores therein underlying said slots and headed bolt means disposed through said slots and threadedly engaged in sAid bores for releasably clamping said parts at said positions.
 6. A rotary crosscutting assembly as claimed in claim 5 in which said one part has at least one recess therein interrupting the associated guide surface, and the means operably related between the parts being disposed in said recess. 